Ongoing investigations by federal agencies must be a huge concern for all parents. The survey shows once more the immediate need for regulations be put in place for testing of the elements which are consumed by children. The huge recalls of toys last year should have been a big warning sign that strict rules are necessary for sure keeps the health of our children.
Now it is the turn of imported jewelry, including China, which has been the subject of scrutiny and already some shipments have been transformed after initial tests showed that they contain high levels of toxic metal cadmium. Withdrawals are already in place for a few brands including "Best friends" charm bracelets In my view, it is the tip of the iceberg.
Claire the chain of stores that sells these toxic bracelet could have avoided the whole episode if they had tests in the House in place. Why should we always respond to a health hazard and not have proactively mandatory and strict regulations in place to protect the safety of our children.
Should insist on a kind of marking that indicates the metal content of the piece of jewellery, and that the jewelry poses no risk to children's health, consumer groups.
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1. Executive Summary
Health concerns over cadmium in children's jewellery began after
analytical testing by Health Canada revealed certain low-cost
children's jewellery contained cadmium at levels up to 93%. It has been
demonstrated, with tragic consequences, that swallowed jewellery may
become lodged in the stomach, leading to the release of large amounts
of lead in certain cases. Although no reported incidents of cadmium
poisoning were found following ingestion of jewellery, it is considered
this may pose an analogous threat. Young children under the age of 4
commonly place non-food items in their mouths, and therefore represent
the group most at risk.
The incidental ingestion of a piece of jewellery must be
considered carefully from a risk assessment perspective, especially
since acute exposure limits have not been well defined for cadmium. A
review of the toxicological literature revealed that no reliable human
data existed in order to define an acceptable one-time ingestion of
cadmium. Therefore, results from animal studies were used to derive an
oral acute provisional minimal risk level (pMRL) of 0.0732 mg/kg bw
for cadmium.
Health Canada analyzed approximately 200 children's
jewellery samples that were judged small enough to fit into a child's
mouth for cadmium content. A subset of these samples were also
subjected to migration testing, which revealed no consistency between
the total amount of cadmium in a sample, and the amount that might be
released in the simulated physiological environment of the stomach over
an extended period (such as in the case of a piece of jewellery lodged
in the stomach over several days). Since standardized migration
testing cannot accurately predict the amount of cadmium that might be
leached out of a sample in such an environment, using total cadmium
content to derive a guideline is considered the most health-protective
approach.
Based on a conservative weight of evidence approach, it is
proposed to restrict the total cadmium concentration in children's
jewellery to 130 ppm (0.013%), as this should protect small children
from the risk of acute toxicity from cadmium following ingestion.
In addition, while risks associated with daily licking or
sucking of a piece of cadmium-containing jewellery were not the primary
focus of this report, a restriction of 130 ppm total cadmium should
also be protective for chronic effects attributable to cadmium.
Note: 130 parts per million (ppm) = 130 mg/kg as a product concentration
2. Introduction
In 2009 and 2010, as part of Health Canada's cyclical
enforcement surveys of children's jewellery, analytical testing
revealed that in addition to lead, cadmium was also present in some
articles of children's jewellery at levels up to 93% (930000 ppm).
Since cadmium is considered likely to pose a risk in children's
jewellery, the Consumer Product Safety Directorate of Health Canada
(hereafter referred to as Health Canada) has undertaken a risk
assessment of cadmium in jewellery intended for young children in order
to propose a product specific guideline.
3. Background
The issue of cadmium exposure from children’s jewellery
followed concerns over another heavy metal, lead. In 2006, a
4-year-old US child (Minneapolis, Minnesota) died from acute lead
poisoning after swallowing a bracelet containing 99.1% lead (CDC,
2006). This case and others have demonstrated that swallowed jewellery
may become lodged in the stomach, which may lead to the release of
large amounts of lead (potentially much greater than that predicted by
standard migration testing). Although no cases of cadmium poisoning
have been reported following the ingestion of jewellery, it is possible
this poses an analogous risk, owing to the known toxicity of this
heavy metal.
Regulatory measures to limit the amount of lead in children’s jewellery exist in Canada (
Children’s Jewellery Regulations under the
Canada Consumer Product Safety Act) and the United States (
Federal Hazardous Substances Act - Interim Policy, 2005;
Consumer Product Safety Improvement Act, 2008).
4. Objectives
The objective of this report is to quantify the acute risk
associated with a one-time ingestion of a cadmium-containing piece of
jewellery by a small child, and to define an acceptable level of
cadmium in children's jewellery.
In addition, chronic risks associated with daily licking or
sucking of cadmium-containing jewellery intended for children will be
evaluated.
5. Existing Exposure Limits
Since the focus of this assessment is on acute poisoning
following ingestion of a piece of cadmium-containing jewellery, only
oral exposure is considered. Several chronic exposure limits exist for
ingested cadmium, which are mainly based on renal toxicity:
- World Health Organization (WHO) Provisional Tolerable Monthly Intake level (PTMI) -25 µg/kg/month (0.8 µg/kg bw/day) (JECFA, 2010).
- U.S. Environmental Protection Agency (EPA) oral reference dose (RfD) - 1 µg/kg bw/day for food intake and 0.5 µg/kg bw/day for cadmium in drinking water (EPA, 1994).
- Agency for Toxic Substances and Disease Registry (ATSDR) minimal risk level (MRL) for chronic oral exposure - 0.1 µg/kg bw/day (ATSDR, 2008). ATSDR MRL for intermediate length exposure - 0.5 µg/kg bw/day based on effects on bone in experimental animals
To date, no regulatory limits have been identified for acute
ingestion of cadmium in any jurisdiction, presumably due to the
uniqueness of this exposure situation, or limitations in the
toxicological database.
6. Review of Toxicological Results (Hazard Characterization)
In 2008, ATSDR published a draft Toxicological Profile for
Cadmium, in which an exhaustive scientific review of cadmium toxicity
was conducted (ATSDR, 2008). Scientific literature since the release
of the ATSDR profile (i.e. 2008 - present) was consistent overall with
regards to the acute toxicity of cadmium. Therefore, the ATSDR profile
is considered the most comprehensive review of cadmium available, and
was used as a source document to evaluate acute hazards following oral
exposure. Selected cases are presented as follows.
Only anecdotal cases of acute cadmium poisoning have been
documented in humans. The most notable reported case described an
unknown number of children who experienced nausea, vomiting, abdominal
cramps and headache following consumption of vending machine beverages
that contained approximately 16 mg/L cadmium (Nordberg et al. 1973). The
dose that induced these toxic effects was estimated to be 0.07 mg/kg
(assuming ingestion of 150 mL and body weight of 35 kg). Although
informative, a high level of uncertainty surrounded this case, and
therefore it was not considered adequate to derive an exposure limit.
From documented studies in animals, a range of health
endpoints was identified, including death, changes in body weight, as
well as renal, hepatic, cardiovascular, hemotological, neurological,
reproductive/developmental, and immunological effects. In addition,
acute gastrointestinal toxicity appears to be a common endpoint
consistent with that of the human poisoning noted above.
The most suitable study for derivation of a critical
endpoint was a short-term study in Sprague Dawley rats (Borzelleca et
al. 1989). In this study, a subset of animals were administered
either 1 or 10 consecutive daily doses of cadmium chloride (CdCl2) by
oral gavage (0, 25, 51, 107, 225 mg/kg). Additional animals were
administered CdCl2 in drinking water for 10 days (calculated doses of
0, 1.8, 12.8, 18.2 mg/kg/day for males, 0, 1.8, 13.3, 22.6 mg/kg/day
for females).
In the 1-day gavage portion of the study (0, 25, 51, 107, 225
mg/kg), mortality was observed in 0/20, 2/20, 1/20, 3/20, and 5/20
animals, respectively. Body weights were decreased, and lung weights
increased in treated males relative to controls. Otherwise, no
significant gross pathological findings were observed at necropsy, and
there were no consistently significant dose-related adverse effects
noted aside from a reported decrease in serum ALP levels (data not
presented). Following 10 consecutive daily gavage doses (0, 25, 51,
107, 225 mg/kg), mortality was observed in 0/20, 3/20, 7/20, 7/20, and
20/20 animals, respectively. In remaining animals, body weight gains
were reduced in a dose-related manner. Treatment-related changes were
also noted for several serum chemistry (ALP, cholesterol and
phosphorus), hematology (hemoglobin, hematocrit, erythrocyte,
leukocytes and platelets) parameters, as well as signs of toxicity in
liver, brain, spleen, lungs, thymus and kidneys. The authors concluded
that 25 mg/kg/day was the apparent No-Observed-Adverse-Effect-Level
(NOAEL).
There were no deaths in the 10-day drinking water study
(calculated doses of 0, 1.8, 12.8 and 18.2 mg/kg/day for males, and 0,
1.8, 13.3 and 22.6 mg/kg/day for females). Dose-related body weight
decreases were noted, although this may have been at least partly
related to the reduced fluid intake by treated animals, presumably due
to the poor palatability of cadmium in water, which has been previously
demonstrated (Cory-Slechta et al. 1981). The authors reported no
evidence of significant compound-related toxicity for rats treated via
drinking water, and considered the highest dose (18-23 mg/kg/day) the
apparent NOAEL. It is acknowledged that minor changes were observed
related to testes, kidney, liver, spleen and thymus, as well as for
other serum chemistry parameters (ALP, 5'-nucleotidase, protein,
glucose, and BUN), but these were most typically observed at the high
dose only. In addition, the toxicological significance of these
findings was unclear, and may have been a secondary signs of reduced
food intake, which could not be verified as this parameter (i.e. food
intake) was not measured on the study.
However, for the purposes of the Health Canada assessment, the
NOAEL for the above study (Borzelleca et al. 1989) was considered to be
the mid-dose (12.8 and 13.3 mg/kg/day for males/females, respectively),
as an added measure of precaution.
Therefore, in the absence of reliable human data, 12.8 mg/kg
(CdCl2) was chosen as the most appropriate acute critical effect level.
7. Characterization of Minimal Risk Level
From the critical effect level described above (12.8 mg/kg bw -
CdCl2), a provisional minimum risk level (pMRL) can be calculated for
cadmium chloride:
pMRL = 12.8 mg/kg bw/(10(intra)×10(inter)) = 0.12mg/kg bw
To determine exposure attributable to elemental cadmium (which
accounts for 61% of CdCl2; MW Cd = 112; MW Cl2 = 70), the pMRL was
adjusted as follows:
pMRL = 0.12 mg/kg bw×0.61 = 0.0732 mg/kg bw
Therefore, for the purpose of this assessment, 0.0732 mg/kg bw
is considered to be a health protective exposure value with regards to a
one-time oral ingestion of elemental cadmium.
8. Child's Exposure Following Ingestion of a Piece of Children's Jewellery
Young children under the age of 4 commonly place non-food
items in their mouths, and therefore represent the group most likely to
ingest a piece of jewellery. Using 13 kg as the average body weight for
a child 7 months to 4 years (Health Canada, Human Health Risk
Assessment for Priority Substances, 1994), an incidental intake of
cadmium at the pMRL for this age group can be calculated as follows:
0.732 mg/kg bw×13 kg = 0.9516 mg
9. Total Cadmium Content versus Migration
In 2009, the Product Safety Laboratory (PSL) of Health Canada
conducted analyses of migratable cadmium in metallic jewellery over 144
hours (project # 2009-1123). Additional analyses of children's
jewellery were performed in 2009 (project 2009-1193) for total cadmium
concentrations in a larger number of children's jewellery products. In
2010, samples from project 2009-1193 that contained total cadmium levels
greater than 100000 ppm (10%) were subjected to extended migration
testing (project 2010-1290). This extended testing interval (i.e. 144
hours) was selected in order to show that migration of cadmium from
children's jewellery might continue after 2 hours (which is the standard
sampling time for migration testing under internationally recognized
guidelines such as EN71-3). Results are presented in the following
figure.
Figure 1 Migratable Cadmium (ppm) in Jewellery Samples over 144 hours
These results demonstrate that for many samples (reduced-scale
graph, bottom right), the 2-hour timeframe may be adequate to predict
migration. For several others however (full-scale graph), cadmium
continued to migrate in the simulated physiological environment of the
stomach (HCl at 37°C) following the 2-hour time point. This suggests
that using a 2-hour migration test may grossly underestimate cadmium
exposure via jewellery lodged in the stomach over the course of several
days, as was observed in the lead-poisoning death in 2006.
Data from PSL project reports 2009-1123 and 2009-1193 was
analyzed to compare total cadmium content with migration results after
2-hours. Results are presented in the following figure.
Figure 2 Total Cadmium versus Migratable Cadmium (ppm)
The above results show no clear correlation between the total
amount of cadmium in a jewellery sample, and the amount that might
migrate out of the sample in the acidic environment of the stomach over
time. Therefore, any exposure scenario based on migration out of a
jewellery sample will potentially underestimate exposure to cadmium.
Hence, it is considered that cadmium limits in children's jewellery
should focus on total cadmium, and not migratable levels.
10. Proposed Guideline for Cadmium in Children's Jewellery
Health Canada compiled the weights of 94 children's jewellery
samples that were considered small enough to fit into a child's mouth
(considered a "small part" according to the Health Canada's Hazardous
Products Act, see Appendix 1). The 95th percentile weight from this set
of samples was 7.31 g (mean 2.8 g). Therefore, 7.31 g (0.0073 kg)
represents a conservative estimate of the heaviest piece of jewellery
that might be ingested by a small child. Since regulatory limits are
product based, total allowable cadmium concentrations derived using the
heaviest piece of jewellery (i.e. containing the largest total amount of
cadmium) would be most protective.
Therefore:
0.9516 mg/0.0073 kg = 130 ppm (0.013%)
Thus, it is considered that restricting the total cadmium
concentration in children's jewellery to 130 ppm (0.013%) would protect
small children from the risk of acute toxicity following ingestion.
Note: 130 parts per million (ppm) = 130 mg/kg as a product concentration
11. Chronic Risks Associated with Children's Jewellery
The risk associated with chronic oral exposure from licking
or sucking a piece of children's jewellery containing cadmium must be
evaluated separately, as the exposure scenario does not include
prolonged direct contact of the jewellery item with stomach acid (HCl)
under physiologic conditions.
The amount of cadmium that might be released in such a
scenario can be reasonably estimated by a saliva surrogate, such as
water. In Product Safety Laboratory project reports 2009-1123 and
2010-1290, migration of high content cadmium jewellery (total content
up to 93%) into water was measured for extended periods. From all
tested samples, the highest level of migration following 2-hours in
water was 13.5 ppm (13.5 mg/kg). Using the same reasoning as above, a
7.31 g piece of jewellery could potentially release 0.1 mg (=13.5 mg/kg
x 0.0073 kg).
For a child aged 7 months to 4 years old (13 kg):
0.1 mg/13 kg = 0.0077 mg/kg bw
Therefore, a child licking or sucking a piece of cadmium containing jewellery
every day for 2 hours
could be potentially exposed at a level of 0.0077 mg/kg bw/day (7.7
μg/kg bw/day). While this is a conservative estimate, this level is
considerably higher than the chronic oral exposure limits described in
Section 2 of this report (ranging from 0.1 to 1 μg/kg bw/day).
Current levels of cadmium in children's jewellery may
therefore also pose an unacceptable risk for chronic effects. However,
it is acknowledged that the poor palatability (i.e. bad taste) of
cadmium may reduce the likelihood of a child licking/sucking of a piece
of high-content cadmium jewellery on a regular basis.
12. Proposed Guideline with Regards to Chronic Risks
Chronic risks should be eliminated by the substantial
reduction of total cadmium levels in children's jewellery to 130 ppm
(0.013%), as proposed in the previous section. As a hypothetical
scenario, assume that a 7.31 g piece of jewellery (i.e. heaviest
ingestible) contains 130 ppm total cadmium (130 mg/kg).
130 mg/kg × 0.0073 kg = 0.950 mg = 950 µg
This means that under the proposed guideline of 130 ppm, a
piece of ingestible jewellery should not contain more than 950 μg total
cadmium. As discussed in the previous example, the highest 2-hour
(water) migration value was 13.5 ppm (13.5 mg/kg). For the purpose of
this report, this value can also be expressed as a ratio (i.e. 13.5
mg/kg x 1 kg/1000000 mg = 0.0000135).
Therefore, the theoretical maximum amount of cadmium that might migrate out of such a sample can be calculated:
950 µg × 0.0000135 = 0.0128 µg
For a child aged 7 months to 4 years old (13 kg):
0.0128 µg/13 kg = 0.001 µg/kg bw
Since this calculated exposure (0.001 µg/kg bw or 0.001 µg/kg
bw/day) is much lower than the chronic oral exposure limits described
previously (0.1 to 1 µg/kg bw/day), the above hypothetical example
demonstrates that a reduction in the total cadmium content of jewellery
to 130 ppm would be protective of chronic effects attributable to
cadmium.
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